The Flywoo Explorer LR4 is arguably probably the greatest sub250 long-range FPV drones in 2025 when paired with the DJI O4 Professional Air Unit. However like several drone, it’s not good. There are a variety of mods and upgrades that may considerably enhance efficiency—corresponding to putting in a range receiver, optimizing antenna and GPS mounting, lowering weight, and a customized PID/filter tune.
Take a look at my full evaluation of the Flywoo Explorer O4 Professional: https://oscarliang.com/flywoo-explorer-lr4-o4-pro/
Range Receiver Improve & Antenna Mounting
The inventory receiver makes use of a single antenna mounted horizontally on the entrance underneath the body. Whereas that is nice for short-range flights, it’s removed from ultimate for long-range flying.
By upgrading to a real range receiver with two antennas, you’ll be able to mount them vertically on either side of the body. This setup ensures that a minimum of one antenna is in line of sight along with your transmitter more often than not, leading to a much more constant and dependable radio hyperlink.
I’m utilizing the RadioMaster RP4TD receiver, get it right here:
It’s a bit too huge to mount contained in the body, so I hooked up it beneath utilizing a tiny 3D-printed TPU strap – I made it free to obtain right here: https://www.thingiverse.com/factor:7062885
I additionally designed an antenna holder you’ll be able to mount on the standoffs, it has a small 10-degree tilt so it stays vertical when cruising ahead. I made the STL file free to obtain right here: https://www.thingiverse.com/factor:7062886
This range receiver, together with the additional antenna, provides about 3g in comparison with the inventory RX. Nonetheless, for the development in sign reliability, I believe it’s nicely value it. Should you don’t fly lengthy vary or are proud of the inventory efficiency, the unique receiver continues to be completely usable.
Optimizing GPS Mounting
Out of the field, the Explorer LR4 takes a very long time to get a GPS 3D repair (Betaflight recommends a minimum of 8 satellites for dependable GPS Rescue). Additionally, I not often noticed greater than 20 satellites, and I believe it’s as a result of Flywoo’s option to mount the GPS underneath the VTX antennas, which introduces important interference.
My answer? Transfer the GPS to the entrance of the drone.
In earlier Explorer variations, this wasn’t an choice as a result of I needed to mount a Bare GoPro up entrance. However due to the DJI O4 Professional’s onboard recording, I not want a separate digicam, releasing up the proper spot for GPS.
I designed a customized front-mounted GPS holder, free to obtain right here: https://www.thingiverse.com/factor:7062882/
You can too safely take away the copper tape from the GPS module to save lots of a bit extra weight.
The development is substantial. After relocating the GPS:
- 3D repair (8 sats) in underneath 1 minute from a chilly begin
- Virtually immediate repair between battery swaps
- Most satellite tv for pc depend elevated to 29
Switching GPS and Receiver UARTs
This mod is elective—however value contemplating in the event you’re mounting the GPS and receiver like I did above, as a result of the inventory cables aren’t lengthy sufficient. It makes extra sense to swap the UART ports (i.e., transfer the receiver to UART5 and the GPS to UART2). This additionally retains the wiring cleaner.
Necessary: The connector pinouts for UART2 and UART5 are totally different (why, Flywoo?!). You’ll must re-pin the wires within the connectors. It’s a little bit annoying however not troublesome.
Weight Discount
I’ve optimized weight on dozens of BNF drones, and the Explorer was really some of the difficult – it’s already fairly nicely optimized, so there are usually not many locations you’ll be able to scale back weight. Additionally it’s corresponding to light-weight drone, saving a number of grams may really feel underwhelming. However in the event you really care about efficiency, a gram right here and there provides up.
Warning: Eradicating {hardware} reduces crash resistance. Proceed at your personal threat.
Right here’s what I did:
- Eliminated arm guards and solely use two screws per motor
- Eliminated the entrance second-row standoffs
- Eliminated copper tape on GPS wires (provided that it’s relocated to the entrance like I did)
- Minimized fabric tape used on motor wires
- Used plastic nuts as an alternative of steel on the FC/ESC stack
- Changed screws (elective):
- High/backside plates: 5mm (was 6mm)
- Stack: 16mm (was 20mm)
- Motors: 5mm (was 6mm)
- Props: 6.5mm (was 7mm)
After performing all these modifications, I used to be capable of shave 9g off my construct. Nonetheless, as a result of I upgraded to a range antenna, it added 3g again. It won’t sound a lot, however that’s 5% weight discount on a quad that’s already extraordinarily light-weight, and may doubtlessly translate to a different 20 to 30 seconds extra flight time.
I believe the DJI O4 Professional air unit has an enormous potential for weight saving too. If we take away the case, heatsink and use lighter antenna options, we might most likely do away with one other 10g or extra. Nonetheless there’s at the moment no such “Bare O4 Professional” conversion package exists (like what Flywoo did with the Bare O3 package), however hopefully, some producers would launch one sooner or later.
You would take into account eradicating the warmth shrink on the battery for a ~2g saving. But it surely’s not really helpful in the event you plan to journey by planes—batteries with out labels won’t go safety. Additionally, you would shorten motor wires which could save one other 2–3g, however I didn’t do it this time.
Because it stands, if you wish to keep underneath 250g, the heaviest battery you need to use is round 80g. The largest battery I can discover is the GNB 4S 850mAh LiHV 60C weighs in at ~73g. Get the it from AliExpress: https://s.click on.aliexpress.com/e/_olJ1Gke
If you wish to get the longest flight time, and weight isn’t a problem, 4S 18650 battery can be the best choice, 30+ minutes of flight time and 20km+ flight distance are attainable. Ideally, you must construct your personal pack utilizing high-quality cells. I like to recommend the Molicel P30B 18650 cells, which I’ve examined right here: https://oscarliang.com/best-18650-li-ion-battery/#Outcomes-and-Suggestions. You can too purchase pre-built Li-ion packs, however they usually use cheaper cells, right here’s a listing of choices: https://oscarliang.com/li-ion-battery-long-range/#Shopping for-Prepared-Made-Li-ion-Battery-Packs
PID & Filter Tuning
The Explorer flies decently out of the field—however I’m dissatisfied Flywoo didn’t even attempt to optimize the filters. Meaning there’s nonetheless room for enchancment, particularly after all of the {hardware} adjustments we’ve made. Fortunately, the Explorer has onboard flash for Blackbox logging, which makes filter tuning attainable.
To your reference, I’ve shared my customized PID and filter tune on Patreon, together with GPS Rescue config, ports, energy settings, charges, OSD format, and extra: https://www.patreon.com/posts/flywoo-explorer-131255399
Need to tune it your self? Begin right here:
Utilizing ND Filters
Get extra cinematic footage by utilizing ND filters. The official DJI ND filters don’t match within the Flywoo Explorer LR4 body, so I like to recommend low-profile ND filters corresponding to those from BetaFPV—they’re additionally among the many most inexpensive choices obtainable: https://oscarliang.com/betafpv-nd-filters-dji-o4-pro/
Discover ways to use ND filters on this information: https://oscarliang.com/nd-filter-fpv/
Different Minor Tweaks
- Disable LED_Strip in Betaflight’s Configuration tab (to scale back CPU load)
- Improve PID Loop Frequency from 2KHz to 4KHz (there’s sufficient CPU headroom)
- ESC Protocol: DShot300
- Present Sensor Scale: 450
- Voltage Sensor Scale: 111
Conclusion
With just some considerate upgrades and modifications, you’ll be able to take the already wonderful Flywoo Explorer LR4 O4 and push it to the subsequent degree—enhancing sign reliability, GPS efficiency, flight efficiency and effectivity, all whereas staying underneath 250g.
In case you are nonetheless debating whether or not to get the Explorer, try my evaluation right here: https://oscarliang.com/flywoo-explorer-lr4-o4-pro/
Let me know what mods you’ve tried—or if there’s something I missed!
